青海玉树尕龙格玛铜多金属矿床地质特征及成因研究

发布时间：2018-02-26 17:13

  本文关键词： 铜多金属矿床 VMS 地质特征 矿床成因 矿化富集规律 尕龙格玛矿床　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：尕龙格玛铜多金属矿床位于青海省玉树地区,大地构造位置属青藏高原碰撞造山带东北部,夹持于金沙江缝合带与龙木错双湖缝合带之间,北羌塘地体北缘,南侧为南羌塘地体,北东侧为松潘甘孜地体,属于三江多金属成矿带。尕龙格玛成矿年龄在晚三叠世,与赋矿地层时代相同。矿区内出露的地层为三叠系巴塘群第二岩组。组成地层的岩石以英安质和安山质的凝灰岩、火山角砾岩及集块熔岩为主,局部夹火山碎屑沉积岩。尕龙格玛矿区位于治多复向斜之次级紧闭背斜地段,核部地层安山质凝灰岩为矿区的含矿岩层,该叠加褶皱控制了尕龙格玛矿床现今的构造形态。矿区内未见侵入岩发育,对安山质凝灰岩进行岩石地球化学研究,表明岩体具有岛弧火山岩特征。尕龙格玛矿床分为东西两个矿区,其中东矿区研究勘探程度较高,目前共圈出铜铅锌矿体6条,铜矿体4条,铅锌(铜)矿体2条。其中2号矿体,为整个区内最为厚大、且品位较高的矿体。其他矿体均为一些隐伏矿体。相对于西矿区各矿体,品位均较高。本次工作主要在东矿区进行。矿体有整合和不整合两类,整合型矿体呈层状、似层状产出于安山质凝灰岩中,不整合型矿体呈脉状和细脉浸染状产于整合型矿体下部。尕龙格玛矿床含矿岩性组合为安山质凝灰岩以及热水喷流沉积岩,如重晶石岩、碧玉岩及铁白云岩等,在矿体的顶板还发育有碳泥质板岩,为热水喷流沉积成矿作用结束的标志。矿区的矿石构造类型主要为条带状构造、块状构造、浸染状构造,其次为脉状构造。矿石中矿物种类繁多,其中金属矿物包括黄铜矿、方铅矿、闪锌矿、黄铁矿、斑铜矿、黝铜矿、辉铜矿、铜蓝和孔雀石等,非金属矿物包括方解石、重晶石、石英和绢云母等。尕龙格玛铜多金属矿床后期改造作用较弱,基本保存了原始热水沉积特征。成矿作用类型主要为热水喷流沉积成矿作用。对与成矿关系密切的重晶石和石英进行包裹体研究得知,成矿期沉积相成矿温度范围为105.2℃-234.2℃;流体盐度范围为0.18-7.58%NaCl eqv;流体密度为0.845-0.995g/cm3而通道相成矿温度范围为251.3℃-360.8℃;流体盐度范围为2.06-7.99%NaCl eqv;流体密度为0.616-0.839g/cm3。氢氧同位素特征显示成矿流体主要为海水,还可能有少量岩浆水混入。硫同位素特征显示成矿流体中的硫主要来自细菌还原的海水硫酸盐或其基底岩石。铅大地构造模式图解显示铅主要来源于上地壳,很可能是成矿热液淋滤下部基底地层带上来。根据尕龙格玛铜多金属矿床大地构造位置、控矿构造、容矿岩石、围岩特征以及矿体形态等基础地质特征及其地球化学特征确定其成因类型为VMS型矿床。
[Abstract]:The Galonggma copper polymetallic deposit is located in the Yushu area of Qinghai Province. The tectonic location is northeast of the collision orogenic belt of the Qinghai-Xizang Plateau, located between the Jinsha River suture zone and the Longmuco Shuanghu suture zone, and the northern margin of the northern Qiangtang terrane. The south Qiangtang terrane is located in the south and the Songpan Ganzi terrane in the north, belonging to the Sanjiang polymetallic metallogenic belt. The strata exposed in the mining area are the second rock formation of the Triassic Batang Group. The rocks that make up the strata are the tuff, volcanic breccia and agglomerate lava, which are mainly composed of lithoclastic and anshanian tuff, volcanic breccia and agglomerate lava. The Galonggma mining area is located in the secondary closed anticline area of Zhiduofuxiao, and the Anshanian tuff is the ore-bearing rock bed of the ore area. The superimposed fold controls the present tectonic form of the Galonggema deposit. No intrusive rocks have developed in the ore area, so the petrogeochemical study of Anshan tuff has been carried out. It shows that the ore body has the characteristics of island arc volcanic rock. The Galonggema deposit is divided into east and west ore areas, and its Middle East ore area has a high degree of research and exploration. At present, there are 6 copper, lead and zinc ore bodies and 4 copper ore bodies in the Middle East. There are 2 lead zinc (copper) orebodies, of which 2 ore bodies are the thickest and higher grade ore bodies in the whole area. The other orebodies are some concealed orebodies. This work is mainly carried out in the east mining area. There are two types of ore bodies: integrated and unconformable. The integrated orebodies are stratiform and bedded in Anshan tuff. The non-integrated orebodies occur in the lower part of the integrated orebodies in the vein and veinlet forms. The ore-bearing rock assemblage of the Galonggema deposit is composed of Anshan tuff and hot water jet sedimentary rocks, such as barite, Jasper and iron dolomite, etc. There are also carbonaceous muddy slate on the roof of the orebody, which is the sign of the end of ore-forming process by hot water jet deposition. The ore structure types of the mining area are mainly banded structure, block structure, disseminated structure, etc. The minerals in the ore include chalcopyrite, galena, sphalerite, pyrite, placerite, tetrahedrite, chalcopyrite, copper blue and malachite, and non-metallic minerals include calcite, barite, etc. Quartz and sericite, etc., the Galonggema copper polymetallic deposit is relatively weak in its late transformation, The primary hot water sedimentary characteristics are basically preserved. The metallogenic types are mainly hydrothermal jet sedimentary mineralization. The study on the inclusions of barite and quartz, which are closely related to the mineralization, shows that the temperature range of metallogenic sedimentary facies is 105.2 鈩，

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